1 Department of Digestive Surgery, Niigata Cancer Center Hospital, 2-15-3, Kawagishicho, Niigata City, Niigata, 951-8566, Japan. maizawa@niigata-cc.jp.
2 Department of Digestive Surgery, Niigata Cancer Center Hospital, 2-15-3, Kawagishicho, Niigata City, Niigata, 951-8566, Japan.